Thanks. I was told I had up to 48 hours after to sign up for the one time payment. When I got there, it allowed me to sign up. Next time, now that I know I can sign up in advance, that's what I'll do. At least it was only one toll charge on one day, so I have only one admin fee. The charge hasn't hit my credit card so I probably won't be charged for it. It's not worth the $15 to try to argue with them.